1. Field of the Invention
The present invention relates to orthopaedic bone plates, and, more particularly, to orthopaedic bone plates attached to an end and shaft of a bone.
2. Description of the Related Art
A bone plate is typically used to maintain different parts of a fractured or otherwise severed bone substantially stationary relative to each other during and/or after the healing process in which the bone mends together. Bones of the limbs include a shaft with a head at either end thereof. The head of a bone has a periphery which is either slightly or greatly enlarged relative to the periphery of the shaft to provide a larger load bearing surface at the end of the bone. Fractures of a bone in the region of the head may be particularly troublesome because of moving and/or soft tissues in the region of the bone joint.
It is known to provide a bone plate which attaches to both a head and the shaft of the bone to thereby maintain the head substantially stationary relative to the shaft. Such a bone plate includes an elongate portion which attaches to the shaft of the bone and a flared portion which attaches to the head of the bone using a plurality of bone screws. The elongate portion and the flared portion are both relatively thick in a direction transverse to the anatomical axis of the bone shaft such that the head and shaft of the bone do not move relative to each other after the bone plate is attached to the bone.
With a conventional bone plate as described above, the flared portion may be curved to accommodate the enlarged curvature of the head. It is quite common for the curvature of the flared portion to not exactly correspond to the curvature of the bone head. Rather, the bone plate has a shape corresponding to a shape of an average bone based upon statistical data. The relatively thick bone plate thus in essence provides a buttress roadmap for the surgeon to reconstruct the bone or place fragments of the bone against the bone plate during the reconstruction.
It is common practice with a thick bone plate as described above for an orthopaedic surgeon to place such a bone plate against the bone, observe the differences in curvature between the bone plate and bone, remove the bone plate and hammer or otherwise bend the bone plate to better fit the bone, and again place the bone plate against the bone. This process is repeated until a satisfactory fit is achieved between the bone plate and the bone.
What is needed in the art is a bone plate which more easily conforms to the shape of a bone without manually and permanently deflecting the bone plate with repeated fitting steps by trial and error.
The present invention provides an orthopaedic bone plate with a flared portion which can deflect toward and thereby conform to the shape of a bone when the elongate portion and flared portion are screwed to the bone. When attached to the bone, the bone plate also acts as a buttress surface with an improved anatomical approximation for smaller bone fragments.
The invention comprises, in one form thereof, an orthopaedic bone plate coupled to a bone having an enlarged head at one end thereof which is attached to a shaft. The bone plate includes an elongate portion, a flared portion and an intermediate portion. The elongate portion is attachable to the bone shaft using a plurality of bone screws. The elongate portion generally defines a longitudinal axis. The flared portion is attachable to the bone head using at least one bone screw. The intermediate portion interconnects the elongate portion and the flared portion. The intermediate portion is structured and arranged to allow the elongate portion and the flared portion to move relative to each other in a direction transverse to the longitudinal axis when the elongate portion and the flared portion are attached to the bone.
An advantage of the present invention is that the bone plate conforms to the shape of the bone by simply screwing the elongate portion and flared portion of the bone plate to the bone.
Another advantage is that the bone plate need not be manually bent or otherwise permanently deformed prior to being attached to the bone.
Yet another advantage is that an improved anatomical approximation of the bone plate is achieved through deflection of the bone plate, thereby resulting in superior bone reduction at the fracture.
A further advantage is that the improved anatomical approximation results in an increased contact interface between the bone plate and bone, resulting in more loading on the bone and less loading on the bone plate with a reduced possibility of fatigue failure of the bone plate.
A still further advantage is that the superior reduction of the bone results in improved loading between the bone pieces at the fracture site, resulting in improved healing.
An additional advantage is that the improved anatomical approximation results in an improved alignment of the articular surface at the joint of the bone, thereby inhibiting premature wear of the bone.